1. Field of the Invention
The present invention pertains to a surgical catheter, and more particularly, a balloon catheter for enlargement of restrictions in blood vessels, arteries or other human tissue.
2. Description of the Prior Art
Prior art balloon catheters have utilized numerous types of structures to expand outwardly to enlarge a restriction such as in a blood vessel, an artery or human tissue, such as the prostrate. One problem in the past with these structures which enlarged on inflation was that the structure did not always return to its original diameter or initial circular configuration.
U.S. Pat. No. 4,456,000 to Sehjeldahl uses a thin rigid material affixed to the distal end of a catheter to form the balloon. Particularly in the use of non-distensible balloons, the initial profiles achieved by wrapping the balloon are much larger than the outer diameter of the catheter shaft and after inflation in the body, the resulting collapsed profile may appear in cross section as a plate extending outward from the center of the catheter. This necessitates use of a larger device to introduce the balloon catheter and presents complication on removal of the device from the body and may potentially damage tissue.
U.S. Pat. No. 4,637,396 to Cook uses a knitted balloon in which the knitting changes shape to accommodate balloon expansion. This allows for higher pressures to be achieved in larger diameter balloons, but does not necessarily deal with initial or collapsed profiles.
U.S. Pat. No. 4,702,252 to Brooks uses a braided balloon which changes in length as it expands and is accomplished by a spring at the proximal hub end of the catheter. This design requires relative motion between various members of the catheter which may be difficult in long length and tortuous passageways.
U.S. Pat. No. 4,762,130 to Fogarty uses an embedded spring to lower the profiles of the balloon. This design also requires relative motion along its length and does not enhance the pressure changing capability of the elastomeric materials.
Hubs incorporated in balloon catheters have on occasion exhibited balloon pressure integrity breakdown where pressure is bled off through various sealment members of the hub. One alternative embodiment discloses an additional sealing member within an inner chamber of the hub to provide ample pressure maintaining capabilities for proper and constant pressure balloon inflation.
The present invention overcomes the disadvantages of the prior art by providing a balloon catheter with braided fibers encapsulated between elastomeric materials and an embedded spring to provide a low balloon profile after pressurization and depressurization.
The present invention also overcomes other disadvantages of the prior art by providing a collapsible spring fixed between the movable points for allowing a greater inflational radius.